Primary Immunodeficiency

A recent issue in JAMA(Jan. 7, 1998 Vol 279, No.1) highlighted the inclusion of immunodeficiency in the differential diagnosis of recurrent infections in both adults and children. Many physicians are vigilant for immunodeficiency in childhood due to the more common presentation during this time. This article notes that consideration needs to be employed for adults as well due to some of the immunodeficiencies presenting in later years. This includes diseases such as Common Variable Immunodeficiency, IgA deficiency and complement deficiency. As research becomes more sophisticated we are learning that some of the disorders may have a mild phenotype due to different mutations allowing initial presentation in adulthood. We have also developed effective tools in combating infections that have allowed people with immunodeficiency to survive into adulthood. Therefore, those physicians who care for adults will also need to be aware of the complexities of some of the immunodeficiency diseases.

The prevalence of primary immunodeficiencies is 1/100,00 excluding IgA and IgG deficiencies. More than 50% of these disorders are in males due to an X-linked inheritance pattern for diseases such as Bruton’s Agammaglobulinemia, Wiskott-Aldrich, Hyper IgM, X-linked SCIDS, and some forms of Chronic Granulomatous Disease.

The immunodeficiencies are often subdivided into one of the four components of the immune system. The first is Cell Mediated or T cell category which includes disorders such as DiGeorge Syndrome (absence of thymus, congenital heart disease and parathyroid abnl). Pts with cell mediated disorders often have problems with autoimmune phenomena and they tend to have viral, fungal, gram (-) or intracellular infections. A good screen for defects in this category is a CBC with diff, checking for lymphopenia and an anergy panel. The second category is antibody mediated or B cell. Classically these people have otitis media, sinusitis or pneumonia with encapsulated organisms such as haemophilus and streptococcus. Diseases such as IgA deficiency, CVID and Bruton’s are disorders with poor immunoglobulin production. A good screen for disorders in this group include immunoglobulin levels. The third category is complement which can present with recurrent infections similar to B cell disorders, but these patients can also present as collagen vascular disease or recurrent Neisserial infections. A good screen for complement is a CH50. (Take note - proper handling is very important.) The last category involves phagocytic cells such as neutrophils. Dysfunction in this category can result in abscess formation. A good screen is a CBC with diff. Too little or too many neutrophils are helpful clues.

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